1. Technical Field
The present disclosure relates generally to the field of data networking and telecommunications. More particularly, in one exemplary aspect, the present disclosure is directed to estimating received error rates over e.g., a bus interface.
2. Description of Related Technology
High-Definition Multimedia Interface (HDMI) is an exemplary digital display interface standard for connecting multimedia data sources to multimedia display devices. Existing HDMI devices generally support video data, audio data, control data, and optionally network connections. Historically, HDMI was developed to improve audio visual (A/V) interface capabilities while still supporting legacy interfaces (e.g., Digital Visual Interface (DVI)). However, legacy signaling standards were designed around assumptions that are no longer accurate for many consumer electronics. Specifically, aggressive device form factors (e.g., those which are very spatially compact, contain metal casings or other components, etc.) may experience link reliability issues which were heretofore unknown.
For example, HDMI uses Transition Minimized Differential Signaling (TMDS) to reduce electromagnetic interference (EMI), and assist in accurate clock recovery. TMDS maps eight (8) bit data to ten (10) bit symbols. The mapping reduces the likelihood of overshooting or undershooting signaling transitions which can contribute to bit errors. Additionally, TMDS ensures that the data has regular transitions, which is required for clock-data recovery. The mapping scheme of TMDS is simple enough to be handled entirely in link layer hardware i.e., without the assistance of higher layer software.
Unfortunately, existing incarnations of HDMI do not have adequate mechanisms for diagnosing link quality during operation. For reasons discussed in greater detail subsequently herein, corrupted HDMI data is indistinguishable from normal HDMI data using conventional error detection techniques. For example, solutions for determining Bit Error Rate (BER) are based on counting the number of erroneous bits during transmission. Since HDMI receivers cannot detect bit errors, such receivers cannot implement traditional BER metrics.
Accordingly, improved methods and apparatus for detecting and/or characterizing connection quality are required for HDMI devices (and other non-HDMI technologies suffering similar deficiencies).